In tropical countries, cheap do it yourself solar, can provide access to abundance of hot water, to eliminate, disease, maintain a better hygiene, and overall, better lifestyle.
Since its already hot to very hot, heat loss of conduction is a minor problem, if enough area is present to collect solar energy. “Cheap Sheet Solar” was innovated by Stefan Nyström 2017, and can let anyone reap the benefit of low cost energy abundance.
For many, the cheapest and best roof covering, is metal sheets, that can readily and easily be converted to solar collectors.
During sunny weather temperature is good enough to fry an egg, on the rooftop sheeting, and the main idea here is to convert this energy, to hot water, that can be used for washing clothes, showering etc.
The roof itself, is already paid for, so what is needed is the means to collect the incoming energy and put it to storage for use later, i n the night, or next day.
In next picture shows a typical sheet that is used for rooftops:
All that is needed to convert the metal sheet is a couple of screws, copper pie, and a slab of concrete.
1 meter pieces of copper piping, is molded inside the underside of the rooftop sheet, 3 screws is placed form the upside, down into the casting, to hold the pipe and the concrete, in future, since the metal will expand heavily, in time, concrete will not be attached firmly anymore, and the screws holds it tight to the metal.
What we want to use is this type of screw, preferable stainless steel, with seal, so no water enters the hole and drips into the house.
Here is a CAD drawing of how the copper pipe and concrete would look, the shape would vary depending on the profile of the sheet.,
The concrete will secure the pipe, and act as a heat sink, to draw energy from the hot roof.
Therefore we want shorter pieces to cover a larger area, to get higher amount of incoming energy translated to the water running in the pipes. Next picture shows the underside with the casted copper pipe, preferably, this casting should be done before the sheet is attached, but can also be done onsite, without removing the sheets.
In tropical areas the typical incoming energy is high: over 4 Kw per meter square, per hour, even higher numbers can be achieved, during summers hottest days. The sheet in the picture below, showing the sheet upside down,with fitted pipes, 4×1 M, measures 2,4×1,2 meters, and therefore has an area of 2,88m2
This gives that the incoming energy, on the roof sheeting , is around 11.52 KW per hour, even more so during peak sunshine. Most of this is of course lost due to convection but well enough to heat some water.
Preferable silicone flexible tubing is used to connect the pipes together, and stone wool insulation can be added, to lower the room temperature ,
the heat is transported into a storage tank, as in a insulated PVC barrel as cheapest option, or a regular solar tank, that also can have additional electric heater element for rainy periods, when sunshine is not prevalent.
a regular solar tank is around 200 USD from China.
A makeshift expansion for the water inside the closed loop hose system can be done by letting one piece of the hose go upwards to the highest point of the roof. The added volume produced by the heating of the carrier fluid will expand into this hose, and prevent over pressure
Secondly a circulating pump and solar controller is added, to control the fluid transporting the energy to the tank.
Cost is around 20 to 30 USD for this controller, found here:
High temp 12V circulating pumps can be found by searching this link:
As of this i release the technology for free, for anyone to use, more details can of course be added to the technologies, but for this i cannot maintain at no cost operation. So if you are prepared to add some funding in the mix many aspects of the development, manufacturing etc can be avoided. Feel free to contact me.
Energy hegemony must end, do your part. Tweet and retweet, spread the message, abundance of cheap solar is here, help it come to fruition.
Air medium update June 25th 2018
To promote an even lower building cost, air can be used instead of a water based circulation system. Ready availability to find proper copper tubing might cause financial problems in some areas.
Right now the price of copper tubing is relatively low, but this might not be the same in the future. For that reason to try to keep the amount of used copper to a minimum will always be a benefit.
A sheet of metal is bent over the roofing sheet to encapsulate and trap air inside. At the ends concrete is used to seal, 1/4 copper tube is inserted at both ends of the encapsulation.
Silicone tubes must be used or 1/4 copper tubing. to connect several air channels together and to the hot water storage tank. The tubes need to be well insulated. If no other means is available, use Styrofoam cut to strips, and hold together with silver tape. Preferable aluminum tape will ward of the ultraviolet radiation and make the tape last for long periods.
Notice that in any case to use tape will not last forever, and needs to be maintained once in a while, and repaired. If possible get high temp professional solar insulation for pipes or tubing, that has a rating of +150 degrees Celsius.
A small air pump, as those used for aquariums will then be used to circulate air, between the heaters and bubbled inside the tank that is used for storing the heated water.
This method will ensure a very high transfer of energy, and cut the need for heat exchanger that will put the price up considerably Additional controllers as is used with the water operated system is then used to control the pump.
If you feel unsure about the performance with this type of solar heater, as for you average air temperature and amount of sunshine, less than 50 USD will bring you a crude prototype to test your situation out before installing the more expensive materials as the complete model has to have. Overall DIY cost with plastic barrel heat storage is 200 USD and produce hot water worth of 750 USD a year. This gets the return of investment to a mere 3,2 months, truly cheap solar heating. If you cant cut and fit the materials yourself, workmanship should total to less than 100 USD.
Investors are needed, contact me for more information, many projects of this type and of greater magnitude is already developed.